Season 6, Episode 1 - “Deep Trouble, Part II”
Callen and Sam are trapped in an armed submarine that terrorists have aimed to hit an aircraft carrier in San Diego. Meanwhile, Hetty defies orders and forgoes her trip to Washington, as the team tries to locate and save Callen and Sam and prevent the terrorist attack.

Season 6, Episode 2 - “Inelegant Heart”
The NCIS: LA team discovers that one of their own is compromised when they investigate the murder of a Navy contractor involved in illegal transactions of confidential data. Meanwhile, Hetty is under investigation in Washington, D.C., when the Department of Justice arrives in L.A. to investigate the team.

Season 6, Episode 3 - “Praesidium”
Hetty receives some shocking news from NCIS director Leon Vance while she is investigated by the Department of Justice in Washington, D.C. Meanwhile, Nell goes undercover as Hetty to protect a fellow team member.

Season 6, Episode 4 - “The 3rd Choir”
The team members desperately search the city when they learn that someone from their past is targeting one of their own. Meanwhile, operational psychologist Nate Getz visits Nell to help her through a traumatic experience.

Season 6, Episode 5 - “Black Budget”
Callen and Sam travel to Mexico to track down the only employee who escaped a professional hit at the Department of Defense. Back in the States, the rest of the NCIS team work to uncover the motive behind the shooting.

Season 6, Episode 6 - “SEAL Hunter”
Sam is arrested for murdering a woman, but Callen and Granger work to clear his name. Meanwhile, Kensi and Deeks discover a link between the victim and a student from Sam’s past.

Season 6, Episode 7 - “Leipei”
A man is murdered by a small drone, and the investigation reveals he was connected to a terrorist group that is planning an attack on Long Beach. With time running out, Nell uses her drone expertise to try to prevent a disaster.

Season 6, Episode 11 - “Humbug”
The team investigates a burglary at a cyber-security company, but Callen must steer clear after Hetty reveals that his girlfriend, Joelle, is one of the lead witnesses. Also, the team discusses their personal holiday travel plans.

Season 6, Episode 12- “Spiral”
Callen is taken hostage when terrorists take control of a building where he is working undercover to investigate an arms dealer. When the NCIS team arrive, they discover the entire building is wired with explosives.

Season 6, Episode 19 - “Blaze of Glory”
When a missile test is hijacked and sent off course, the team searches for the hacking group responsible for the attack with the help of a young computer specialist Hetty brings in to assist the team. Also, Nell sees the bond between the tech guru and Eric and she becomes jealous.

Season 6, Episode 20 - “Rage”
Callen and Sam resume their undercover identities as a prisoner and guard to infiltrate a white supremacist group believed to be in possession of stolen nuclear material, while Kensi transforms herself into a tattooed biker to play the part of Callen’s girlfriend. Also, Callen’s first meeting with Hetty is revealed.

Season 6, Episode 21 - “Beacon”
Callen and Sam are shocked when an old acquaintance, who they thought was the recent victim of a murder, appears and asks for their help. As the team investigates, they uncover a possible breach of America's economic sanctions against Russia.

Season 6, Episode 2 - “Inelegant Heart”
The NCIS: LA team discovers that one of their own is compromised when they investigate the murder of a Navy contractor involved in illegal transactions of confidential data. Meanwhile, Hetty is under investigation in Washington, D.C., when the Department of Justice arrives in L.A. to investigate the team.

Season 6, Episode 3 - “Praesidium”
Hetty receives some shocking news from NCIS director Leon Vance while she is investigated by the Department of Justice in Washington, D.C. Meanwhile, Nell goes undercover as Hetty to protect a fellow team member.

Season 6, Episode 4 - “The 3rd Choir”
The team members desperately search the city when they learn that someone from their past is targeting one of their own. Meanwhile, operational psychologist Nate Getz visits Nell to help her through a traumatic experience.

Season 6, Episode 5 - “Black Budget”
Callen and Sam travel to Mexico to track down the only employee who escaped a professional hit at the Department of Defense. Back in the States, the rest of the NCIS team work to uncover the motive behind the shooting.

Season 6, Episode 6 - “SEAL Hunter”
Sam is arrested for murdering a woman, but Callen and Granger work to clear his name. Meanwhile, Kensi and Deeks discover a link between the victim and a student from Sam’s past.

Season 6, Episode 7 - “Leipei”
A man is murdered by a small drone, and the investigation reveals he was connected to a terrorist group that is planning an attack on Long Beach. With time running out, Nell uses her drone expertise to try to prevent a disaster.

Season 6, Episode 11 - “Humbug”
The team investigates a burglary at a cyber-security company, but Callen must steer clear after Hetty reveals that his girlfriend, Joelle, is one of the lead witnesses. Also, the team discusses their personal holiday travel plans.

Season 6, Episode 12- “Spiral”
Callen is taken hostage when terrorists take control of a building where he is working undercover to investigate an arms dealer. When the NCIS team arrive, they discover the entire building is wired with explosives.

Season 6, Episode 19 - “Blaze of Glory”
When a missile test is hijacked and sent off course, the team searches for the hacking group responsible for the attack with the help of a young computer specialist Hetty brings in to assist the team. Also, Nell sees the bond between the tech guru and Eric and she becomes jealous.

Season 6, Episode 20 - “Rage”
Callen and Sam resume their undercover identities as a prisoner and guard to infiltrate a white supremacist group believed to be in possession of stolen nuclear material, while Kensi transforms herself into a tattooed biker to play the part of Callen’s girlfriend. Also, Callen’s first meeting with Hetty is revealed.